Elemental chlorine and bromine are effective biocides. However, their low solubility (less than 1 and 4 wt %, respectively), and increasing safety requirements as well, limit their use as a biocide in industrial applications. Aqueous solutions of active chlorine are widely used in bleaching processes, treatment of swimming pool water and as disinfectant. It is well known that upon addition to water, active oxidizer species of halogen comprise HOX, and XO− (where X stands for Cl or Br). The aqueous halogen solutions are susceptible to decomposition during storage and prior to use, losing their beneficial properties. An aqueous halogen solution is unstable and emits very pungent fumes. Mixtures of aqueous halogen solutions with stabilizers have been used, usually strongly alkaline, the stabilizers usually comprising sulfamate. EP 0570044 describes a stable solution of elemental bromine and urea in water for disinfection, bleaching, and etching.
Biofouling is an undesired accumulation of organisms or their products, or products of their decomposition in liquid volumes or on wet surfaces; particularly, biofouling comprises microorganisms, such as bacteria, fungi, algae, etc. Biofouling is found in almost all circumstances where water based liquids are in contact with other materials. Biofouling is controlled by a variety of methods, including coating the endangered surfaces, or applying biocides in their vicinity. It is an object of this invention to provide a simple, cheap, antifouling method.
It is another object of this invention to provide an antifouling method without using caustic alkali materials.
It is another object of this invention to provide an antifouling method utilizing concentrated compositions which can be easily and safely manipulated and diluted for use, and which are stable on prolonged storage.
It is still another object of this invention to provide an antifouling method utilizing active halogen compositions which are stable on prolonged storage and efficient when used as biocide.
It is a still other object of the invention to provide an efficient biocide for the treatment of water with high TOC content.
It is a further object of the invention to provide an efficient biocide for reducing or preventing bio-contaminations in aqueous liquids or on surfaces in contact with aqueous liquids, utilizing stable aqueous solutions comprising a mixture of active halogen and urea or its derivatives.
Other objects and advantages of present invention will appear as description proceeds.